Legionnaires' Disease Outbreaks from Hospital Drinking Water Preventable with Disinfection, New Study Gives Evaluation Criteria to Control Legionella
February 27, 2011
Legionella experts give a stepwise approach to evaluate efficacy of disinfection methods. Authors recommend infection control practitioners lead environment of care team in choosing disinfection technologies; post-treatment followed by scheduled culturing for Legionella.
Legionnaires’ disease outbreaks, caused by Legionella in hospital drinking water, can be prevented using the right disinfection methods. Too often hospitals make treatment decisions on marketing claims not science.
A research review paper, “Controlling Legionella in Hospital Drinking Water: An Evidence-Based Review of Disinfection Methods,” published in Infection Control and Hospital Epidemiology, gives decision makers standard criteria to evaluate and choose the most effective Legionella disinfection methods for their facilities.
Legionella experts and authors Yusen E. Lin, PhD, MBA, National Kaohsiung Normal University, Kaohsiung, Taiwan; Janet E. Stout, PhD, director of Special Pathogens Laboratory and University of Pittsburgh Swanson School of Engineering; and Victor L. Yu, MD, University of Pittsburgh, rate the efficacy of systemic disinfection, focal disinfection, and short-term disinfection methods used in outbreak situations. They offer a four-step approach to assist hospitals in choosing the most effective method.
Choosing the right method or combination of methods reduces the risk of patients contracting Legionnaires’ disease. Stout and her colleagues strongly recommend that infection control practitioners lead the environment of care team in choosing the best disinfection methodology. They also advocate for scheduled routine monitoring through culturing to ensure safe water.
“Hospitals relying on facilities managers and vendors in selecting a disinfection method may not be basing their decisions on evidence-based research. Our paper shows that some disinfection methods work better than others,” says Dr. Stout, who along with Dr. Yu discovered the link between Legionella pneumophila in hospital drinking water and hospital-acquired Legionnaires’ disease in 1982.
Common Legionella disinfection methods include: copper-silver ionization, chlorine dioxide, monochloramine, ultraviolet light, and hyperchlorination, (systemic disinfection); point-of-use filtration, (focal disinfection); superheat-and-flush with or without hyperchlorination (short-term disinfection methods in outbreak situations).
Hyperchlorination or heat and flush are often used during an outbreak, but are the least effective. Copper-silver ionization has fulfilled the four-step criteria for demonstrating efficacy.
The author’s four-step evaluation process of disinfection systems includes ensuring the technology kills Legionella. This step is followed by a review of anecdotal experience for controlling Legionella contamination in hospitals, followed by literature review of peer-reviewed and published reports of controlled studies of years of efficacy for hospital-acquired Legionnaires’ disease. Finally, to confirm with multiple hospitals that disinfection methods worked.
“We hope this review will assist hospitals in choosing a method that is safe, efficient and cost-effective,” says Stout.
Large Cooling Water Systems with “Green” Nonchemical Devices Need Monitoring, Legionella Expert to Present Pitt Study Results at CTI Conference
February 03, 2011
Large Cooling Water Systems with “Green” Nonchemical Devices Need Monitoring, Legionella Expert to Present Pitt Study Results at CTI Conference
40 percent to 60 percent of all cooling water systems tested contain Legionella--the bacterium that causes Legionnaires’ disease. Nonchemical devices failed to control this bacterium in model cooling water towers according to an ASHRAE funded study.
To avoid a potential health hazard, equipment operators, building owners, and engineers should monitor large cooling water systems that use nonchemical “green” devices to control Legionella, says Dr. Janet Stout, who will present results from a recent American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)-funded study on the effectiveness of NCDs at the Cooling Technologies Industry conference in San Antonio, February 6-10.
“Large cooling systems are energy efficient and, if properly treated, very safe, but our study results show that nonchemical devices alone may not control microbial growth,” says Stout, director of Special Pathogens Laboratory, and research associate professor in civil and environmental engineering at the University of Pittsburgh Swanson School of Engineering. Stout conducted the Pitt study with environmental engineering chair and lead investigator Radisav Vidic, William Kepler Whiteford Professor, and then-graduate student Scott Duda, project manager, Special Pathogens Laboratory.
Cooling towers for hospitals, hotels, and other large commercial buildings provide the perfect environment for bacterial growth. These conditions include: water temperature; biofilm caused by scale and other organic material; stagnant water; pooled water in fittings, piping, and, gaskets. To date, most of these cooling water systems aren’t tested for Legionella—the bacterium that causes Legionnaires’ disease. According to numerous studies, of those water systems that have been tested 40 percent to 60 percent contained Legionella.
Stout, a leading expert in detection and prevention strategies for Legionnaires’ disease, recommends adding chemical treatment, when needed, as one possible measure to control microbial growth and prevent a potential health hazard.
Currently, both CTI and ASHRAE are reviewing the adoption of standards for Legionella. At the CTI conference, attendees will discuss CTI Standard 159 – Legionellosis: Related Practices for Evaporative Cooling Water Systems.
Pitt Study Suggests Nonchemical Water Treatments Touted As “Green” Fail to Prevent Bacterial Growth in Air-Cooling Systems Found in Hospitals, Large Buildings
December 10, 2010
Five devices pitched as alternatives to chemical water treatment for water-based air-conditioning systems allowed the same rate of bacterial growth as untreated water, Pitt researchers found in two-year study.
Read more (link to NCD)
Alcohol-Based Wipes Significantly More Effective than Rubs in Reducing Bacteria and Spores; Findings Could Impact Hospital-Acquired Infections
November 03, 2010
Special Pathogens Laboratory Study First to Test 2002 CDC Recommendations that Alcohol-Based Rubs More Effective
Alcohol-based gels and hand rubs dominate the market for hand hygiene products, but that may start to change due to a new study conducted by Special Pathogens Laboratory (SPL) to determine which was more effective—wipes or rubs.
Revisiting the hand wipe versus gel debate: Is a higher-ethanol content hand wipe more effective than an ethanol rub? Published in the November issue of the American Journal of Infection Control, this study shows that wipes-towelettes saturated with alcohol are more effective than popular alcohol-based hand rubs in reducing some bacteria on hands.
"Our study gives infection control professionals more information so they can make evidence-based decisions when evaluating hand sanitizer products," says Janet E. Stout, PhD, director of SPL, and associate research professor at the University of Pittsburgh Swanson School of Engineering.
"With more effective hand hygiene products, we stand a better chance in reducing hospital-acquired infections that result in 90,000 patient deaths and $4.5 billion in medical expenses annually," says Dr. Stout.
Dr. Stout, who along with her colleagues at SPL and the University of Pittsburgh, Natalie N. D'Antonio, MS; John D Rihs, BS; and Victor L. Yu, MD, conducted and coauthored the study which measured the effectiveness of an ethanol wipe (PDI Sani-Hands® ALC) against an ethanol rub (Purell®) in eliminating bacteria.
In addition to the wipe’s effectiveness against bacteria, the study also demonstrated the wipe is equal to or more effective in physically removing spores from the surface of contaminated hands than the ethanol alcohol-based hand rub. According to the authors, the wipes’ “effectiveness in removing spores was due to the mechanical wiping action employed during product usage.” People using hand rubs cannot achieve this mechanical wiping action, which requires a cloth material. Spores, like bacteria, can cause infections. Clostridium difficile is one such spore-forming bacteria that causes life threatening inflammation of the colon and is transmitted to patients while hospitalized for other problems.
After inoculating subjects’ hands with bacteria, the researchers disinfected them with a wipe of 65.9% ethanol alcohol or rub containing 62% ethanol alcohol, and then tested for the presence of bacteria. The results showed the wipe “was significantly more effective” than the rub in reducing the number of viable bacteria and spores on the hands.
While the study’s main aim was to compare wipes and rubs, Dr. Stout and her team also compared the two products to antibacterial soap (Kindest Kare®). The soap proved more effective in reducing both bacteria and spores than either the wipe or rub. One important point: soap requires water-usually through a sink-but the wipe and rub does not require water.
Eight years after the Centers for Disease Control and Prevention issued guidelines stating that alcohol-based hand wipes weren’t as effective as alcohol-based hand rubs, this study shows that with the higher alcohol content, wipes were more effective than rubs.
October 28, 2010
June 22, 2010
Dr. Janet Stout, director of Special Pathogens Laboratory, recently represented the United States in the "Conference to Prevent Legionellosis - Italy Meets the U.S."
During her keynote speech, Dr. Stout highlighted to the Italian Legionella Prevention Committee the importance of prevention as outlined in the Allegheny County Guidelines. Stout states, "The overall perception we have that drinking water in the home [and in the acute and chronic care setting] is free of bacteria is a misconception," said Stout.
August 18, 2008
The Pittsburgh Central Keystone Innovation Zone announced Monday it has awarded about $73,000 in grants in its first round of giving. Special Pathogens Laboratory, provider of microbiology services located in the city’s Uptown section, received $18,493
October 15, 2007
Hospital engineers often go to guidance documents for help in preventing Legionnaires' disease. While advisory documents from health authorities and professional societies provide guidelines for approaches to prevention, a consensus opinion for prevention of this disease does not exist.
Published in ASHRAE Journal, October 2007. ©Copyright 2007 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. and is posted with permission.
September 30, 2007
by Dehlia Ricks
September 30, 2007
The bacterial infection got its name 31 years ago, when dozens of attendees at an American Legion's convention in Philadelphia came down with an inexplicable illness that caught experts off guard. To this day, Legionnaires' disease is a mystery.
Scientists know without question that Legionella, the bacterium that causes the disease, is a water-loving microbe that thrives in soil and is capable of colonizing in air conditioning systems, hot water tanks and other drinking water systems. What they've begun to more precisely document is its ubiquity in the environment and the various ways it can be transmitted.
The recent cluster of Legionnaires' cases on Long Island has triggered widespread testing at two residential facilities for elderly people. Results of sampling from one of those centers, Sunharbor, a nursing home in Roslyn Heights where two residents with the disease died, has traced Legionella to a cooling tower involved in the air conditioning system. The tower is not a usual hiding place for the bug, said Janet Stout, director of Special Pathogens Laboratory at the University of Pittsburgh where scientists focus on the study of Legionella.
"The majority of cases are caused by colonies in warm-water distribution systems because there is a presence of organic nutrients, what we would call biofilm," she said.
Stout said Legionella is one of the easiest bugs to prevent in health care settings just by being vigilant. But she and her colleagues estimate that 50 percent to 70 percent of all buildings worldwide, health care institutions included, have water systems that are contaminated by Legionella.
"I always described the family of Legionella as a big one," said Stout, who, along with her colleague, Dr. Victor Yu, a professor of medicine at the university, is calling for more rigorous testing and treatment standards, steps that can prevent unnecessary infections in hospitals and nursing homes. In all, there are 41 subtypes of Legionella, Stout said.
"One member, Legionella pneumophila, causes 90 percent of all infections, and it is the one that caused the outbreak in Philadelphia in 1976," Stout said.
This past week, state health officials confirmed seven cases of Legionnaires' disease on Long Island. Samples are still being evaluated from the Sunrise Assisted Living facility in Smithtown, where five residents were infected, including one who died. State and local health officials say because the residents who died were elderly and suffered from numerous medical conditions Legionnaires' may not be the sole cause of death.
Stout said even when the source of the bacteria is found, it is not always a simple task determining exactly how people become infected.
Dr. Pascal Imperato, who chairs the department of preventive medicine at SUNY Downstate Brooklyn, said the notion that people contract Legionnaires' through showering is one of the enduring myths about the disease.
Imperato, who was New York City's health commissioner in 1976, was one of the experts called upon to help solve the Legionnaires' disease mystery. He said much of what was learned about Legionella during the outbreak evolved from intense brainstorming by scientists and public health officials who wanted to quickly understand how the convention-goers were infected - and with what kind of organisms. A clue arose from a scant mention in the scientific literature of the late 1940s, which discussed a little-known bacterium with the potential to cause serious disease.
Now, experts are aware that elderly people in nursing homes can contract the organism through feeding tubes and other medical apparatus that would allow people to aspirate the microbe. Legionella is not spread person to person.
Copyright © 2007, Newsday Inc. Reprinted with permission.
August 27, 2007
Tribune-Review, August 22, 2007
National infection control policies should be changed to include regular testing of hospital water systems for bacteria that cause a particularly deadly form of pneumonia, according to a study led by the University of Pittsburgh School of Medicine.
Pitt announced today that a 20-hospital study showed that monitoring institutional water systems can help predict the risk of hospital-acquired Legionella pneumonia, better known as Legionnaires' disease. The disease was named after it was identified as causing an outbreak of pneumonia in 1976 among attendees at an American Legion convention in Philadelphia.
"Only those hospitals that had high levels of Legionella bacteria in their water systems had patients who contracted Legionnaires' disease," Dr. Victor L. Yu, professor of medicine at Pitt and senior author of the study, published in the journal Infection Control and Hospital Epidemiology, said in a statement. "Proactive monitoring of the hospital water supply alerted physicians to the hidden risk of Legionnaires' disease for their patients."
Currently the U.S. Centers for Disease Control and Prevention recommends that hospitals and other health care institutions monitor patients for pneumonia before testing water systems for Legionella.
Legionnaires' has an average fatality rate of 28 percent and is estimated to be responsible for up to 20,000 cases each year in the United States. Pitt's study involved hospitals in 14 states. Researchers retrieved water samples from at least 10 sites at each hospital on multiple occasions from 2000 to 2002. When cases of Legionnaires' were identified, patients were tested.
The researchers found that 70 percent of the hospital water systems tested positive for Legionella and 43 percent had high levels of bacteria colonization. All patient cases of Legionnaires' were traced back to the hospitals with high-level colonization.
"Our study provides much-needed evidence to support a national policy change to include routine environmental surveillance of health care facility water systems along with stringent clinical monitoring of patients," Janet Stout, a research assistant professor in Pitt's department of civil and environmental engineering and first author of the paper, said in a statement. "We think this long-overdue approach should be adopted by infection control and infectious disease practitioners nationwide."